The present invention relates to an allele of petunia designated green corolla 1-1 (gc1-1), which results in altered flower color and/or flower color pattern. The present invention also relates to a petunia seed, a petunia plant and parts of a petunia plant, a petunia variety and a petunia hybrid which comprise the mutant allele. In addition, the present invention is directed to transferring the gc1-1 allele in the petunia plant to other petunia or calibrachoa varieties and species and is useful for producing new types and varieties of petunia. 
The geographic origin of Petunia is South America, where various species have been found in Argentina, Brazil, Bolivia, Paraguay, and Uruguay. The primary locations for species diversity are mostly limited to the three Brazilian provinces of Parana, Santa Catarina, and Rio Grande do Sul particularly along river banks and isolated areas (Sink ed., Petunia: Monographs on Theoretical and Applied Genetics, Springer-Verlag: Berlin, Germany (1984)).
Jussieu first established the genus Petunia in 1803. Since that time, the Petunia genus has undergone constant restructuring and is still somewhat unsettled today. Fries wrote the first Petunia monograph in 1911 where he proposed the division of the genus into two distinct subgenera, Pseudonicotiana and Eupetunia. Species in the subgenera of Pseudonicotiana had long, narrow corolla tubes, while species in the subgenera Eupetunia had short, wide corolla tubes (Sink ed., Petunia: Monographs on Theoretical and Applied Genetics, Springer-Verlag: Berlin, Germany (1984)).
The cultivated garden petunia, Petunia×hybrida, is not a true species but actually a complex interspecific hybrid of two or more Petunia species. In earlier literature, many taxonomists and scientists suggested that as many as five different species including P. axillaris, P. integrifolia, P. parodii, P. inflata, and P. violacea all contributed to the origin of P.×hybrida. Even today there is still disagreement over whether many species of Petunia, like P. inflata, P. occidentalis, and P. parodii, are actually true species or are subspecies of either P. integrifolia or P. axillaris (Wijsman, Acta Bot. Neerl. 31: 477-490 (1982), Griesbach and Beck, HortScience 35(7): 1347-1349 (2000) and Mishiba et al., Annals of Botany 85: 665-673 (2000)).
During the 1980s and 1990, H. J. Wijsman published a series of articles regarding the ancestry of P.×hybrida and the inter-relationship of several species classified as Petunia. These studies discovered that P.×hybrida and its ancestral species, P. nyctaginiflora (=P. axillaris) and P. violacea (=P. integrifolia), possessed 14 pairs of chromosomes while several other species, including P. parviflora, possessed 18 pairs of chromosomes. Since P. parviflora was the lectotype species for the Petunia genus, Wijsman and J. H. de Jong proposed transferring the 14-chromosome species to the genus Stimoryne. Horticulturists opposed reclassifying the garden petunia and in 1986, Wijsman proposed the alternative of making P. nyctaginiflora the lectotype species for Petunia and transferring the 18-chromosome species to another genus. The I. N. G. Committee adopted this proposal. By 1990 Wijsman had transferred several species, including P. parviflora (=C. parviflora) to Calibrachoa, originally established by Llave and Lexarza in 1825. Calibrachoa parviflora (=C. mexicana Llave & Lexarza) is now the type species for the genus Calibrachoa. 
In the horticultural industry, petunias are found in a variety of forms for landscape, home garden, and container use. Marketable series have been developed for upright, spreading and semi-trailing to trailing growth habits. Leaf colors range from light to dark green and can have variegated types. Flower colors range from white, yellow, and shades of pink, rose, salmon, red, burgundy, and purple with mixtures found in a variety of patterns. Flower color patterns include morn, having a throat color that extends to the petal area, picotee, having an outer margin of another color, star, having two colors one of which forms a star, veined, having pronounced venation of a darker color. Flower types include both double and single. Single and double flower petunias are further categorized as grandiflora or multiflora types. Grandiflora petunia plants typically having large flowers with wide sepals, thick filaments, and large stigmas. It is inherited as a single dominant gene. Multiflora petunia plants typically having small flowers with narrow sepals, thin filaments, and small stigmas. It inherited as a single recessive gene. Although multiflora-type flowers are smaller than grandiflora type, the multiflora types are further divided into small and large flower sizes.
There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possess the traits to meet the program goals. The goal is to combine in a single variety or hybrid an improved combination of desirable traits from the parental germplasm. These important traits may include flower color and size, number of flowers, improved plant vigor, resistance to diseases and insects, and tolerance to drought and heat.
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F1 hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection.
The complexity of inheritance influences choice of the breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, overall value of the advanced breeding lines, and number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.).
Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s). The best lines are candidates for new commercial cultivars; those still deficient in a few traits are used as parents to produce new populations for further selection.
These processes, which lead to the final step of marketing and distribution, usually take from eight to 12 years from the time the first cross is made. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.
The goal of petunia plant breeding is to develop new, unique and superior petunia plants. The breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. The breeder has no direct control at the cellular level. Therefore, two breeders will never develop the same line, or even very similar lines, having the same petunia traits.
With each cross, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The varieties which are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. This unpredictability results in the expenditure of large research funds to develop a superior new petunia variety.
Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The varieties which are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same line twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large research monies to develop superior new petunia varieties.
Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued.
Backcross breeding has been used to transfer genes for a simply inherited, highly heritable trait into a desirable homozygous cultivar or inbred line which is the recurrent parent. The source of the trait to be transferred is called the donor parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent are selected and repeatedly crossed (backcrossed) to the recurrent parent.
The development of commercial petunia hybrids typically requires the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Pedigree breeding and recurrent selection breeding methods are used to develop inbred lines from breeding populations. Breeding programs combine desirable traits from two or more inbred lines or various broad-based sources into breeding pools from which inbred lines are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred lines and the hybrids from these crosses are evaluated to determine which have commercial potential.
Commercially available petunia varieties are primarily F1 hybrids. In F1 hybrid varieties, pollen from an inbred “male” line is used to pollinate an inbred, but genetically different “female” line. The resulting F1 hybrids are both phenotypically highly uniform and vigorous. In addition to this hybrid vigor, hybrids also offer opportunities for the rapid and controlled deployment of dominant genes. A homozygous dominant gene in one parent of a hybrid will result in all F1 hybrids expressing the dominant gene phenotype. Within the seed trade industry, F1 hybrids command the preeminent role because of their superior vigor, uniformity and performance.
Descriptions of other breeding methods that are commonly used for different traits and crops can be found in one of several reference books (e.g., Principles of Plant Breeding, John Wiley and Son, pp. 115-161, 1960; Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987).
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification.